AMD-762 Datasheet, PDF (35/122 Pages) Advanced Micro Devices – System Controller

24416C—December 2001
Preliminary Information
AMD-762™ System Controller Data Sheet
33-MHz PCI Bus
The AMD-762 system controller provides the three 66-MHz
clocks required for the Southbridge and the two PCI bus slots
in this mode. If a 33-MHz-only card is inserted in one of the
66-MHz PCI slots, then the M66EN signal is deasserted, which
causes the AMD-762 system controller to drive 33 MHz on the
PCI_66CLK[2:0] pins.
The 66-MHz PCI mode is illustrated in Figure 7.
An alternate mode of PCI bus operation is illustrated in Figure
8 on page 24, and simply supports a standard 33-MHz PCI
Southbridge and up to seven PCI slots.
In this mode, all PCI devices operate at 33 MHz and clocking is
provided by the motherboard clock generator chip.
100/133 MHz
66 MHz
66 MHz
33 MHz
AGP Slot
Clock
Generator
33 MHz
DDR DIMMs
SYSCLK
AGPCLK
AMD-762™ System Controller
Northbridge
PCICLK
CLKOUT[0]n
CLKOUT[1]n
CLKOUT[2]n
CLKOUT[3]n
PCI_66CLK[0]
PCI_66CLK[2]
PCI_66CLK[1]
AMD-768™ Peripheral
Bus Controller
32-bit, 33-MHz PCI Bus Slots
64-bit, 66-MHz
PCI Bus Slots
33-MHz PCI Clocks
Figure 7. System Clocking with 66-MHz PCI Primary Bus
Chapter 2
Functional Operation
23